Juncus rugulosus
Wrinkled rush
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Family: Juncaceae · Type: Grass · Native
Juncus rugulosus (Wrinkled rush) is a native California grass in the Juncaceae family, recognized by distinctive wrinkled surfaces throughout plant.
Wrinkled rush is a California native perennial found in southern Sierra Nevada Foothills, central and southern California Coast Ranges, southern California, Transverse and Peninsular Ranges, and desert mountains in wet places at elevations below 2,100 meters. Flowering from late spring to summer, this plant produces brown to reddish-brown flowers in dense clusters with small, bristle-tipped flower parts. Growing as a densely matted herb 15 to 70 centimeters tall with a stout horizontal rhizome, it forms intricate ground-covering patches. Its leafless stems have prominent scarious sheath appendages and cylindric blade-like stems with crosswalls, creating a distinctive woven appearance. The fruit emerges longer than the perianth, displaying a three-angled shape with a long beak and a bright reddish-brown coloration.
Identification and appearance
Key characters: 55 sympatric species; distinctive wrinkled surfaces throughout plant
Habitat and range
Habitat: Common. Wet places
Elevation: < 2100 m
California counties: Los Angeles, Riverside, San Bernardino, San Diego, Kern, Monterey, Orange, Ventura, Tulare, Inyo, Santa Barbara
Outside California: Baja California
How to tell it apart
vs Schoenoplectus: Juncus has leaf blades present; Schoenoplectus is leafless with only bladeless sheaths at base.; vs Carex: Juncus has round or flattened stems; Carex has triangular stems you can feel.; vs Luzula: Run finger along leaf edge - smooth = Juncus, hairy = Luzula.; vs Elegia: Juncus has small individual flowers; Elegia has showy papery bracts and branching structure.; vs Cyperus: Juncus has round stems and capsules; Cyperus has triangular stems and lens-shaped achenes.
Frequently asked questions
Is Juncus rugulosus native to California?
Yes. Juncus rugulosus is native to California (recorded as native).
Where in California does Juncus rugulosus grow?
Juncus rugulosus occurs in Los Angeles, Riverside, San Bernardino, San Diego, Kern, Monterey, Orange, Ventura and other counties, at elevations of < 2100 m.
What plant family does Juncus rugulosus belong to?
Juncus rugulosus is in the Juncaceae family, genus Juncus.
What habitat does Juncus rugulosus grow in?
Juncus rugulosus grows in Common. Wet places.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · Index of California Plant Names · CalPhotos
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.